#include <bits/stdc++.h>

#define F first
#define S second
#define pb push_back
#define all(x) x.begin(), x.end()
#pragma GCC optimise ("ofast")
#pragma GCC optimise("unroll-loops")

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

const int N = 200000 + 10;
const ll MOD = 1000000000 + 7;
const ll INF = 1000000000000000000;
const ll LOG = 25;
const int H = 313;

int n, p, q, can[N];
ll ps[N];
pii a[N];

bool isval(int x){
	for (int i = x; i <= n; i++){
		ll sum = ps[i] - ps[i - x];
		if (a[i].F * 1ll * x * 1ll * q <= sum * p) return 1;
	}
	return 0;
}

void Main(){
	cin >> n;
	for (int i = 1; i <= n; i++){
		int x;
		cin >> x;
		a[i] = {x, i};
		ps[i] = 0;
		can[i] = 0;
	}
	sort(a + 1, a + n + 1);
	int l = 1, r = n + 1;
	cin >> p >> q;
	for (int i = 1; i <= n; i++) ps[i] = ps[i - 1] + a[i].F;
	while (r - l > 1){
		int md = (l + r) >> 1;
		if (isval(md)) l = md;
		else r = md;
	}
//	cout << "AFA " << l << endl; 
	for (int i = l; i <= n; i++){
		ll sum = ps[i] - ps[i - l];
		if (a[i].F * 1ll * l * 1ll * q <= sum * p) can[i] = 1;
		else can[i] = 0;
	}
	for (int i = 1; i <= n; i++) ps[i] = ps[i - 1] + can[i];
	vi ans;
	for (int i = 1; i <= n; i++){
		if (ps[min(i + l - 1, n)] - ps[i - 1] == 0) ans.pb(a[i].S);
	}
	cout << ans.size() << '\n';
	sort(all(ans));
	for (auto u:ans) cout << u << ' ';
	cout << '\n';
	return;
}

int main(){
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	int t;
	cin >> t;
	while (t--) Main();
	



}